The present invention relates a shifting arrangement for an automatic transmission of a motor vehicle controlled by an electronic control unit, having a selector lever. The movement of the selector lever in a shifting channel causes coherent transmission gears to be preselected.
From the German Patent Document DE 38 07 881, a shifting arrangement is known for a power-shiftable transmission for a selectively automatic or manual shifting in a motor vehicle. In this case, the shifting arrangement comprises a selector lever guided in an H-shaped gate. One of the two shifting channels arranged in the longitudinal direction of the motor vehicle has the selector lever positions P, R, N, D, 3, 2, 1 which are customary for an automatic transmission, while, in the shifting channel that is in parallel to it, by movement the selector lever, an upward shifting by one gear can take place in the driving direction, and a downward shifting by one gear can take place against the driving direction.
It is an object of the present invention to improve a shifting arrangement of the above-described type so that the transmission can be shifted more easily and in a manner that increases the driving safety.
These and other objects are achieved in the present invention which provides a shifting arrangement for an automatic transmission of a motor vehicle controlled by an electronic control unit, comprising a shifting channel, a selector lever and a manual gear selecting device. The selector lever is in the shifting channel and is movable in the shifting channel to preselect different transmission gears. The selector lever is movement in the shifting channel into at least one of two positions in which a manual gear selecting device can trigger shifting commands. The manual gear selecting device is coupled to the electronic control unit which triggers shifting commands for shifting forward gears of the transmission.
This shifting arrangement permits the selective automatic or manual shifting of a power-shiftable transmission with a selector lever which is guided in only one shifting channel. The forward gears, which in the earlier-described German Patent Document DE 38 07 881 are shifted in a second shifting channel by movement of the selector lever, are instead shifted by a manual gear selecting device according to the present invention.
According to an embodiment of the present invention, this gear selecting device is formed by a rocker switch arranged on the selector lever which transmits shifting commands to an electronic control unit only if the selector lever, in a shifting channel enlarged by the M-position (=Manual), was brought into this M-position. As a basis for the upshifting or downshifting by one gear in the M-position, the gear which is present and automatically selected when the selector lever is moved out of the D-position (=Drive), is taken into the M-position.
In a variant of this embodiment, the shifting channel only has the conventional positions P (=Parking), R (= Reverse), N (=Neutral) and D. In the D-position of the selector lever, the automatic gear selection is suppressed by a switch which is constructed as a push button and is arranged on the selector lever, and by means of the rocker switch, a shifting command can be triggered for an upshift or downshift.
In a second embodiment of the invention, the manual gear selecting device is constructed as a steering column switch and is arranged on the steering column holding the steering wheel of the motor vehicle. In this embodiment, the shifting channel of the selector lever has either the positions P, R, N, D, M or the positions P, R, N, D. In one embodiment, manual shifting commands are possible only in the M-position of the selector lever by means of the swivelling of the steering column switch.
Another embodiment of the present invention permits the triggering of manual shifting commands in the D-position of the selector lever after an axial displacement of the steering column switch, while the automatic gear selection remains suppressed. This suppressing is canceled by a second axial displacement of the steering column switch, and a manual gear selection is not possible.
A second variant of this embodiment gives shifting commands of the steering column switch in the D-position of the selector lever priority over the automatic gear selection so that a first-time axial displacements of the switch is not necessary. A one-time axial displacement of the switch after the triggering of manual displacement commands again permits the automatic gear selection.
An advantage of this second embodiment is the transferring of the manual gear selecting device into the proximity of the steering wheel and thus into the direct reach of the driver. This increases the driving safety because both hands may remain on the steering wheel and a possibly required eye contact with the selector lever is superfluous.
According to a third embodiment of the invention, the shifting channel of the selector lever is placed on the steering column, and the manual gear selecting device is integrated in the selector lever. In this case, the shifting channel has the positions P, R, N, D, M or the positions P, R, N, D. In the M-position, manual shifting commands are triggered by movement of the selector lever transversely to the shifting channel.
The variant of this embodiment requires no M-position, but permits a manual gear selection in the D-position after a first-time axial displacement of the selector lever. The return to the automatic gear selection is triggered by a second axial displacement.
A second variant of this embodiment gives priority to manual commands by displacement of the selector lever in the D-position so that the automatic gear selection is suppressed. A return to the automatic gear selection is possible by means of a one-time axial displacement of the selector lever.
All embodiments of the invention have a simplified operation in common. The shift gate with only one shifting channel which is known in conventional automatic transmissions was kept so that the swivelling of the selector lever into a second shifting channel is not required.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.